Light-distribution system for photocomposers

ABSTRACT

A system for directing light in a photocomposer to a selected character to participate in the formation of an image thereof. The photocomposer has a maxtrix provided with characters uniformly arranged in rows which are adapted selectively to be positioned at a projecting position where a selected character in the row at the latter position can have its image projected onto a light-sensitive member. A plurality of elongated light-guide members are respectively provided with light-discharge ends respectively aligned with the characters in a row at the projecting location, and these light-guide members have lightreceiving ends distant from their light-discharge ends. A single light source is provided for illuminating a selected character, and a light-directing structure coacts with this single light source to direct light therefrom to the receiving end of a selected light-guide member, so that light will travel therethrough to the discharge end thereof for illuminating a selected character in a row which is at the projecting location.

35o-9e.24 se j I as Elinited States Fa sfiee ase Naltajima 5] Dec. 25, 1973 LIGHT-DESTREBUTION SYSTEM FOR [57] ABSTRACT PHQTQC0M?0SERS Tohru Nakajima, Tokyo-to, Japan Primary Examiner-10hn M. Horan Attorney-Steinberg & Blake A system for directing light in a photocomposer to a selected character to participate in the formation of an image thereof. The photocomposer has a maxtrix provided with characters uniformly arranged in rows which are adapted selectively to be positioned at a projecting position where a selected character in the row at the latter position can have its image projected onto a light-sensitive member. A plurality of elongated light-guide members are respectively provided with light-discharge ends respectively aligned with the characters in a row at the projecting location, and these light-guide members have light-receiving ends distant from their light-discharge ends. A single light source is-provided for illuminating a selected character, and a light-directing structure coacts with this single light source to direct light therefrom to the receiving end of a selected light-guide member, so that light will travel therethrough to the discharge end thereof for illuminating a selected character in a row which is at the projecting location.

3 Claims, 3 Drawing Figures PATENTED 1975 1111 I; L HHHHU Q w Ilium,

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O O O Q CD O INVENTOR TOA'RU NAKAJ/MA BACKGROUND OF THE INVENTION The present invention relates to photocomposers.

In particular, the present invention relates to a system for distributing the light to a selected character of a photocomposer.

Photocomposers are conventionally provided with a matrix carrying a plurality of characters. For example the matrix may take the form of a negative film sheet having the plurality of characters and mounted on a rotary cylinder or disc so that a row of the characters of the matrix can be located at a position suitable for projecting an image of a selected character. This image is projected onto a light-sensitive member such as a film sheet. These photocomposers are conventionally provided with light source for each line or row of characters from which is selected the character whose image is to be imprinted. These lines or rows of characters are turnable about a given axis and light guides are provided for respectively directing light from the several light sources to the rows of characters.

A character is selected from the matrix on the revolving cylinder or disc first by a character code which identifies the circumferential or radial line in which the selected character is located and which then brings about illumination, such as by a flash discharge tube, at that one of the light sources which will direct light through a light guide aligned with the selected character when the row in which the latter is located becomes properly positioned for projection of an image of the selected character. It is thus essential with these conventional devices that there be a number of light sources equalling the number of characters which are arranged in each line or row in the matrix.

Considering for example the case ofa cylinder which carries the matrix, in a practical construction of the above type the number of characters which can be contained in a circumferential line along the cylinder is limited by the diameter thereof, and there is an additional limitation, corresponding to the speed of photocomposition, in accordance with the number of revoltuions that the revolving cylinder can carry out in a given unit of time. These limitations depend upon the dynamic strength of the revolving cylinder, on the one hand, and upon the allowable out-of-focus range permitting satisfactory photographic reproduction of the characters to be carried out, these factors being determined by the relationship between the circumferential or rotary speed with which the characters move and the effective duration of the flash illumination, on the other hand. The number of characters which can be practically arranged along a circumferential row surrounding a cylinder axis is of the order of 500, so that, for example, it would be possible to provide a revolving cylinder with a capacity of 10,000 characters if 20 circumferential lines of characters are provided, and such an arrangement would of course require 20 distinct illuminating systems.

Such a relatively large number of light sources creates serious problems in practical operation because of the difficulties resulting from the adjustment of the light intensity among the several lines or rows of characters. In addition, experience has shown that serious problems are encountered in maintenance operations involved in the exchange of flash discharge tubes and adjustment of light intensity after the exchange.

SUMMARY OF THE INVENTION it is accordingly a primary object of the present invention to provide for photocomposers a lightdistribution system which will avoid the above drawbacks.

In particular, it is an object of the present invention to provide a light-distribution system which is capable of using only a single iight source for all of the characters.

An additional object of the present invention is to provide a construction of this type which is exceedingly simple and rugged, greatly reducin the complexities encountered in conventional photocomposers.

Yet another object of the present invention is to provide a light-distribution system capable of being used in photocomposers irrespective of whether the matrix is arranged along a cylinder or along a disc, the flexibility of the system of the invention enabling its design to be easily modified in order to direct light from a single light source to any selected character irrespective of the manner in which the characters are arranged.

It is also an object of the present invention to provide a construction which will enable light to be directed from a single light source td" a selected character with a relatively small amount of movement required for only an extremely small part of the illuminating system of the invention.

Also, it is an object of the present invention to provide an illuninating system which is extremely compact so that it can easily be accommodated within a relatively small space in a photocomposer.

According to the invention the photocomposer has a matrix provided with characters arranged uniformly in rows which are respectively adapted to be located at a projecting location where a selected character in the row at the latter location can have its image projected onto a light-sensitive member. A plurality of elongated light-guide means respectively terminate in lightdischarge ends which are respectively aligned with the characters in a row which is at the projection location,

so that light traveling along the light-guide means will discharge from the discharge ends thereof toward the characters to participate in the formation of images thereof. These light-guide means have, respectively, light-receiving ends situated distant from their lightdischarge ends along a predetermined circle in which the light-receiving ends of the plurality of light-guide means are arranged almost equidistantly. A single light source is provided for directing light along an axis which contains the center of the latter circle, and a light-directing means is provided for directing the light from the light source to the receiving end of a selected light-guide means. In this way the light will discharge from the discharge end of the selected light guide means toward a selected character in a row which is at the projecting location.

BRIEF DESCRIPTION OF DRAWINGS The invention is illustrated by way of example in the accompanying drawings which form part of this application and in which:

FIG. 1 is a schematic fragmentary partly sectional illustration of one possible embodiment of a lightdistribution system according to the invention;

FIG. 2 is a plan view schematically representing the light-directing means of the invention and the arrangement of the light-receiving ends of the light-guide means with respect thereto; and

FIG. 3 is a fragmentary schematic elevation of another embodiment of a light-directing means and lightguide means of the invention.

DESCRIPTKON OF PREFERRED EMBODlMENTS Referring to the drawings and to FIG. 1 in particular, the structure of the invention includes only a single light source l which provides a source of flash illumination. This single light source 1 thus may take the form of a flash discharge tube such as a xenon discharge tube. A condenser lens 2 is positioned for receiving light from the light source 1 in order to direct a parallel bundle of light rays along a predetermined axis.

Situated along this latter axis is a light-directing means which includes a rotary light reflector d in the form of a mirror or prism having a light-reflecting surface which extends across the axis along which the light rays travel from the condenser 2 at an angle of 45. Thus the light will be reflected by the reflector 4 so as to travel horizontally therefrom, as viewed in FIG. 1. In the illustrated example the light-directing means includes a diaphragm 3 through which the reflected bundle of light rays passes.

The structure of the invention also includes a plurality of light-guide means 6 in the form of elongated bars made of a known material through which light can be guided, the light being received at light-receiving ends of the plurality of light-guide means 6,respectively, and traveling along the interior thereof to discharge from the light-discharge ends 6' thereof. As is apparent particularly from FIG. 2, the several light-receiving ends of the plurality of light-guide means 6 are directed toward the axis around which the light-directing means rotates, this axis coinciding with the optical axis of the source 1 and the condenser 2, and in addition these lightreceiving ends are arranged equidistantly from each 1 other along a circle the center of which is contained in the axis along which the light travels from the source 1. Thus, in accordance with the angular position of the light-directing means at any given instant the light will be reflected thereby to the light-receiving end of a selected light-guide means 6. in the position of the part shown in FIG. 2 the light is directed to the receiving end of the right light-receiving means 6. In the particular example illustrated in FIG. 2 there are eight lightguide means 6 having their receiving ends circumferentially distributed uniformly about the optical axis of the light source 1..

the several light-guide means 6 are respectively curved so as to have configurations which will provide them with the light-discharge ends 6' arranged along a line parallel to the axis 11 of a rotary cylinder 8 carrying the matrix 7 which in the illustrated example is provided with eight circumferential lines of characters equidistantly arranged in each circumferential line of characters so as to provide axial rows of characters. Each axial row of eight characters, in the illustrated example, is capable of being positioned at the projecting location shown in FIG. 1 for the lowermost axial row of characters. It will be noted that the discharge ends 6' are respectively aligned with the characters in the axial row of the matrix? which is at the projecting location shown in FlG. 1. Moreover, the light-discharge ends 6 are situated within the hollow cylinder 8 which carries the matrix 7.

The light-directing means further includes a pulse or stepper motor 5 capable of stepping the reflector 4 around the optical axis of the light source 1 so as to reflect the light horizontally through the diaphragm 3 to the receiving end ofa selected light-guide means 6. The operation of the components is synchronized so that at a given instant the flash of illumination from the single light source 1 is created when the reflector 4 will direct the light to the receiving end of a selected light-guide means 6 so that the light traveling through the selected light-guide means will discharge from the discharge end 6' thereof in order to illuminate a selected one of characters in the axial row at the projecting location. The pulse motor 5 can rotate in both directions so that the maximum angle of rotation is while the minimum angle of rotation is 45 with the particular example illustrated where there are eight light-guide means 6 and eight characters in each row which can be positioned at the projecting location. Thus, by using the rotary light-directing means of the invention it is possible to direct light from a single light source to a selected one of the light-guide means, thus eliminating the requirement of a number of light sources equal to the number of characters in each row which can be positioned at the projecting location.

The light discharging from the end 6 of the selected light-guide means 6 will illuminate a selected character so that the image thereof can travel through one of the apertures 9. These apertures respectively register with the characters or the cylindrical wall of the cylinder 8 can be provided with circumferential grooves 9 formed with openings which register with characters. As is schematically shown in HO. 1 there are eight objectives 10 respectively focused on the characters in the row at the projecting location, and there is a camera objective l2 capable of receiving the bundle of parallel rays from the objectives l0 and focusing the image on the light-sensitive material 13. As is shown schematically in FIG. 1, the pulse motor 5 is connected through a control system to a pulse motor which rotates the shaft M which is fixed to the cylinder 8 so that the latter is turned in synchronism with the reflector 4.

The embodiment of the invention which is illustrated in FIG. 3 has the light-receiving ends of the plurality of light-guide means 6 arranged in a circle situated in a plane normal to the optical axis of the light source 1, so that in this case the light-receiving ends are not directed toward the optical axis of the light source 1 but instead are situated in a plane normal to the optical axis. In this case the stepper motor 55 rotates a plate 16 which carries a prism 14 provided with an outer lightreflecting surface which turns along a circle of the same diameter as that along which the light-receiving ends of the plurality of light-guide means 6 are arranged but axially displaced from this latter circle. The prism 14 has an inner reflecting surface extending across the optical axis of the light source 1 in the same way as the reflecting surface of the reflector 4. The plate 16 carries a counterbalance 15 to balance the weight of the prism 14. Beneath the outer reflecting surface of the prism 14 the plate 16 is formed with an aperture through which the light travels to the light-receiving end of the selected light-guide means 6. Otherwise the embodiment of FIG. 3 is identical with that of FIG. 1.

It is apparent, therefore, that with the present invention there is an extremely simple illuminating optical system for the automatic photocomposer. 'lhis simple light-distributing system of the invention is highly advantageous both from the standpoint of manufacturing costs and from the standpoint of maintenance costs. Thus, lack of uniformity in light intensity among a plurality of light sources is avoided by the provision of a single light source. Only one flash discharge tube need be exchanged. The absolute value of the light intensity may be adjusted by regulating the input power of the single flash discharge tube or by the adjusting effect of a neutral density filter placed in the path of light travel.

What is claimed is:

i. For use in automatic photocomposer which has a matrix provided with characters which are uniformly arranged in rows which are adapted to be selectively situated at a projecting location where a selected character in the row at said location can have its image projected onto a light-sensitive member, a plurality of elongated light-guide means respectively terminating in light-discharge ends respectively directed toward and aligned with the characters in a row at said projecting location for discharging light toward the characters in said row at said projecting location for participating in the formation of an image of a selected character, said plurality of light-guide means respectively having lightreceiving ends situated distant from said light-discharge ends thereof, so that light received by the lightreceiving end of a selected one of said light-guide means will be guided by said latter light-guide means to the discharge end thereof for illuminating a selected character in a row at said projecting location, a single light source, and light-directing means coacting with said single light source and with said light-receiving ends of said plurality of light-guide means for directing light from said source to a light-receiving end of a selected one of said light-guide means for illuminatinga selected character in a row which is at said projecting location, said light-receiving ends of said plurality of light-guide means being arranged equidistantly from each other along a given circle which surrounds an axis which contains the center of said circle, and said lightdirecting means including a rotary member turnaole about the latter axis for directing light from said source to the receiving end of a selected light-guide means, said light-receiving end of said plurality of light-guide means being situated in a common plane which is normal to said axis, said light-directing means including 1' rotary member having a light-reflecting surface turnable along a second circle of the same diameter as said first-named circle and situated in a plane parallel to that in which the light-receiving ends of said plurality oflight-guide means are located for receiving light traveling radially from said axis and for reflecting the light in a direction parallel to said axis to the light'receiving end of a selected light-guide means.

2. The combination of claim 1 and wherein said refleeting surface of said rotary member forms an outer reflecting surface thereof, said member having an inner reflecting surface extendingacross said axis for reflecting light traveling along said axis to said outer reflecting surface, and said light source directing light along said axis to said inner reflecting surface.

3. The combination of claim 2 and wherein said rotary member of said light-directing means is in the form IINITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,7 3 Dated December 25, 1973 Inventor-(s) TOhIU. Nakajima It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

On the cover sheet in the heading, item should read as follows:

- Foreign Application Priority Data: v

Japan a December 26, 1969 L B/2135 Signed and sealed this 18th day of June (sEAL) Attest: v

c. MARSHALL DANN EDWARD M.FLETCHER,JR.

Commissioner of Patents Attesting Officer uscoMM-oc wan-Poe i H's. GOVERNMENT PRINT'NG OFFICE Z i." 0-36'33l, 

1. For use in automatic photocomposer which has a matrix provided with characters which are uniformly arranged in rows which are adapted to be selectively situated at a projecting location where a selected character in the row at said location can have its image projected onto a light-sensitive member, a plurality of elongated light-guide means respectively terminating in light-discharge ends respectively directed toward and aligned with the characters in a row at said projecting location for discharging light toward the characters in said row at said projecting location for participating in the formation of an image of a selected character, said plurality of light-guide means respectively having light-receiving ends situated distant from said light-discharge ends thereof, so that light received by the light-receiving end of a selected one of said light-guide means will be guided by said latter light-guide means to the discharge end thereof for illuminating a selected character in a row at said projecting location, a single light source, and light-directing means coacting with said single light source and with said light-receiving ends of said plurality of light-guide means for directing light from said source to a light-receiving end of a selected one of said light-guide means for illuminating a selected character in a row which is at said projecting location, said light-receiving ends of said plurality of lightguide means being arranged equidistantly from each other along a given circle which surrounds an axis which contains the center of said circle, and said light-directing means including a rotary member turnable about the latter axis for directing light from said source to the receiving end of a selected light-guide means, said light-receiving end of said plurality of light-guide means being situated in a common plane which is normal to said axis, said light-directing means including a rotary member having a light-reflecting surface turnable along a second circle of the same diameter as said first-named circle and situated in a plane parallel to that in which the light-receiving ends of said plurality of light-guide means are located for receiving light traveling radially from said axis and for reflecting the light in a direction parallel to said axis to the light-receiving end of a selected light-guide means.
 2. The combination of claim 1 and wherein said reflecting surface of said rotary member forms an outer reflecting surface thereof, said member having an inner reflecting surface extending across said axis for reflecting light traveling along said axis to said outer reflecting surface, and said light source directing light along said axis to said inner reflecting surface.
 3. The combination of claim 2 and wherein said rotary member of said light-directing means is in the form of a prism. 